System for detecting a latent image using an alignment apparatus
US5496669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 1994 |
| Grant date | Mar 5, 1996 |
| Priority date | — |
| Expiry date | Jun 27, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70675
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The system comprises a latent image detection device comprising an alignment device which uses non-actinic radiation (10) and which is intended for aligning the mask pattern with respect to the substrate (3) and is designed for detecting the measure of coincidence of a mask alignment feature and a substrate alignment feature (8). The alignment device is provided with a radiation-sensitive detection system (6) which is connected to an electronic signal circuit in which the amplitude of the radiation incident on the detection system is determined, which originates from a latent image, formed in the photosensitive layer, of a mask feature, in which a spatial frequency occurs which is approximately equal to the useful resolving power of the projection lens system and considerably greater than the resolving power of the alignment device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.